In order to meet the needs for a reduction in the size of an electronic device and an increase in the speed thereof, a reduction in size and an increase in speed are also required in a technique for mounting a semiconductor device. Flip-chip bonding is adopted in various electronic devices as a method of mounting a semiconductor device, on account of the advantage in that the mounting area of a semiconductor device can be reduced and the length of a wiring can be shortened as compared with wire bonding.
The term “flip-chip bonding” refers to a mounting method in which a plurality of terminals of a semiconductor device such as an IC and a plurality of terminals of a wiring substrate are caused to face each other, and the respective terminals are collectively connected to each other with a bump such as solder interposed therebetween in a facedown manner (see, for example, Patent Document 1). In order to protect a wiring, a photosensitive insulating film is provided as a solder resist.